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Extend CTE patch to support recursive UNION (ie, without ALL). The

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implementation uses an in-memory hash table, so it will poop out for very
large recursive results ... but the performance characteristics of a
sort-based implementation would be pretty unpleasant too.
This commit is contained in:
Tom Lane
2008-10-07 19:27:04 +00:00
parent 059349be0c
commit 0d115dde82
13 changed files with 345 additions and 74 deletions
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38
src/backend/optimizer/plan/createplan.c
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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.249 2008/10/04 21:56:53 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.250 2008/10/07 19:27:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2545,10 +2545,13 @@ RecursiveUnion *
make_recursive_union(List *tlist,
Plan *lefttree,
Plan *righttree,
int wtParam)
int wtParam,
List *distinctList,
long numGroups)
{
RecursiveUnion *node = makeNode(RecursiveUnion);
Plan *plan = &node->plan;
int numCols = list_length(distinctList);
cost_recursive_union(plan, lefttree, righttree);
@ -2558,6 +2561,37 @@ make_recursive_union(List *tlist,
plan->righttree = righttree;
node->wtParam = wtParam;
/*
* convert SortGroupClause list into arrays of attr indexes and equality
* operators, as wanted by executor
*/
node->numCols = numCols;
if (numCols > 0)
{
int keyno = 0;
AttrNumber *dupColIdx;
Oid *dupOperators;
ListCell *slitem;
dupColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);
dupOperators = (Oid *) palloc(sizeof(Oid) * numCols);
foreach(slitem, distinctList)
{
SortGroupClause *sortcl = (SortGroupClause *) lfirst(slitem);
TargetEntry *tle = get_sortgroupclause_tle(sortcl,
plan->targetlist);
dupColIdx[keyno] = tle->resno;
dupOperators[keyno] = sortcl->eqop;
Assert(OidIsValid(dupOperators[keyno]));
keyno++;
}
node->dupColIdx = dupColIdx;
node->dupOperators = dupOperators;
}
node->numGroups = numGroups;
return node;
}